<!DOCTYPE html>
<html lang="zh-CN">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width,initial-scale=1">
    <title>图-cnblog | 凌歆的博客</title>
    <meta name="generator" content="VuePress 1.9.5">
    <link rel="icon" href="/img/favicon.ico">
    <meta name="description" content="web前端技术博客,专注web前端学习与总结。JavaScript,js,ES6,TypeScript,vue,React,python,css3,html5,Node,git,github等技术文章。">
    <meta name="keywords" content="前端博客,个人技术博客,前端,前端开发,前端框架,web前端,前端面试题,技术文档,学习,面试,JavaScript,js,ES6,TypeScript,vue,python,css3,html5,Node,git,github,markdown">
    <meta name="baidu-site-verification" content="7F55weZDDc">
    <meta name="theme-color" content="#11a8cd">
    
    <link rel="preload" href="/assets/css/0.styles.d9c8cf8c.css" as="style"><link rel="preload" href="/assets/js/app.57550e13.js" as="script"><link rel="preload" href="/assets/js/2.f014c35f.js" as="script"><link rel="preload" href="/assets/js/114.e95a0131.js" as="script"><link rel="prefetch" href="/assets/js/10.03a98811.js"><link rel="prefetch" href="/assets/js/100.145e708e.js"><link rel="prefetch" href="/assets/js/101.098ca5c8.js"><link rel="prefetch" href="/assets/js/102.4d45c69a.js"><link rel="prefetch" href="/assets/js/103.499de505.js"><link rel="prefetch" href="/assets/js/104.c2c1b9b6.js"><link rel="prefetch" href="/assets/js/105.4e9b0663.js"><link rel="prefetch" href="/assets/js/106.9bb8cf6f.js"><link rel="prefetch" href="/assets/js/107.a81b32d7.js"><link rel="prefetch" href="/assets/js/108.81511e67.js"><link rel="prefetch" href="/assets/js/109.6a6741bf.js"><link rel="prefetch" href="/assets/js/11.e8729182.js"><link rel="prefetch" href="/assets/js/110.de657fe7.js"><link rel="prefetch" href="/assets/js/111.b092af6d.js"><link rel="prefetch" href="/assets/js/112.2dca5709.js"><link rel="prefetch" href="/assets/js/113.dbed1fac.js"><link rel="prefetch" href="/assets/js/115.2e3e8285.js"><link rel="prefetch" href="/assets/js/116.e64f7fec.js"><link rel="prefetch" href="/assets/js/117.583552c9.js"><link rel="prefetch" href="/assets/js/118.aa5d18f0.js"><link rel="prefetch" href="/assets/js/119.0c7b52d7.js"><link rel="prefetch" href="/assets/js/12.d63acec2.js"><link rel="prefetch" href="/assets/js/120.13f86281.js"><link rel="prefetch" href="/assets/js/121.e2b5b7f9.js"><link rel="prefetch" href="/assets/js/122.5252216a.js"><link rel="prefetch" href="/assets/js/123.8b8a3503.js"><link rel="prefetch" href="/assets/js/124.60df855c.js"><link rel="prefetch" href="/assets/js/125.f073ab1c.js"><link rel="prefetch" href="/assets/js/126.7b73de6a.js"><link rel="prefetch" href="/assets/js/127.4e25971c.js"><link rel="prefetch" href="/assets/js/128.0edf0e06.js"><link rel="prefetch" href="/assets/js/129.5cb5a70a.js"><link rel="prefetch" href="/assets/js/13.2259ef71.js"><link rel="prefetch" href="/assets/js/130.00247fda.js"><link rel="prefetch" href="/assets/js/131.d6fc003a.js"><link rel="prefetch" href="/assets/js/132.1a32b18f.js"><link rel="prefetch" href="/assets/js/133.e46c0193.js"><link rel="prefetch" href="/assets/js/134.a6ad681f.js"><link rel="prefetch" href="/assets/js/135.2fcbe137.js"><link rel="prefetch" href="/assets/js/136.f69bf451.js"><link rel="prefetch" href="/assets/js/137.b9ef2fcc.js"><link rel="prefetch" href="/assets/js/138.7fdd9feb.js"><link rel="prefetch" href="/assets/js/139.a3a37c91.js"><link rel="prefetch" href="/assets/js/14.0d6b23b9.js"><link rel="prefetch" href="/assets/js/140.a7c013ae.js"><link rel="prefetch" href="/assets/js/141.956c36ce.js"><link rel="prefetch" href="/assets/js/142.5aacfe42.js"><link rel="prefetch" href="/assets/js/143.57d691ef.js"><link rel="prefetch" href="/assets/js/144.b1e5766e.js"><link rel="prefetch" href="/assets/js/145.463284b7.js"><link rel="prefetch" href="/assets/js/146.6cc6420c.js"><link rel="prefetch" href="/assets/js/147.5b78c5a2.js"><link rel="prefetch" href="/assets/js/148.8d1d7679.js"><link rel="prefetch" href="/assets/js/149.4e0eb213.js"><link rel="prefetch" href="/assets/js/15.f6fde69d.js"><link rel="prefetch" href="/assets/js/150.b183de37.js"><link rel="prefetch" href="/assets/js/151.729ae770.js"><link rel="prefetch" href="/assets/js/152.b1297018.js"><link rel="prefetch" href="/assets/js/153.bb991bca.js"><link rel="prefetch" href="/assets/js/154.6f2286aa.js"><link rel="prefetch" href="/assets/js/155.6a9c7e4d.js"><link rel="prefetch" href="/assets/js/156.f7bd535d.js"><link rel="prefetch" href="/assets/js/157.64c0065c.js"><link rel="prefetch" href="/assets/js/158.d31ae949.js"><link rel="prefetch" href="/assets/js/159.7daea8a7.js"><link rel="prefetch" href="/assets/js/16.7be21beb.js"><link rel="prefetch" href="/assets/js/160.33cc971a.js"><link rel="prefetch" href="/assets/js/161.1676442a.js"><link rel="prefetch" href="/assets/js/162.71378046.js"><link rel="prefetch" href="/assets/js/163.99e49959.js"><link rel="prefetch" href="/assets/js/164.306f07d2.js"><link rel="prefetch" href="/assets/js/165.170977c7.js"><link rel="prefetch" href="/assets/js/166.f8602525.js"><link rel="prefetch" href="/assets/js/167.eea5c001.js"><link rel="prefetch" href="/assets/js/168.0146a311.js"><link rel="prefetch" href="/assets/js/169.05f9c9d9.js"><link rel="prefetch" href="/assets/js/17.2543f471.js"><link rel="prefetch" href="/assets/js/170.25d602b2.js"><link rel="prefetch" href="/assets/js/171.1ada26a6.js"><link rel="prefetch" href="/assets/js/172.2a0f697c.js"><link rel="prefetch" href="/assets/js/173.230d8ca8.js"><link rel="prefetch" href="/assets/js/174.e3758a2b.js"><link rel="prefetch" href="/assets/js/175.0f19f8ea.js"><link rel="prefetch" href="/assets/js/176.bf70d37d.js"><link rel="prefetch" href="/assets/js/177.4400f272.js"><link rel="prefetch" href="/assets/js/178.85af7b89.js"><link rel="prefetch" href="/assets/js/179.4cfaaaa2.js"><link rel="prefetch" href="/assets/js/18.394415f8.js"><link rel="prefetch" href="/assets/js/180.449c8409.js"><link rel="prefetch" href="/assets/js/181.73276924.js"><link rel="prefetch" href="/assets/js/182.5fab25cc.js"><link rel="prefetch" href="/assets/js/183.ecd4934d.js"><link rel="prefetch" href="/assets/js/184.246092cf.js"><link rel="prefetch" href="/assets/js/185.c671cd86.js"><link rel="prefetch" href="/assets/js/186.49bd1963.js"><link rel="prefetch" href="/assets/js/187.1fb32764.js"><link rel="prefetch" href="/assets/js/188.7c6885e9.js"><link rel="prefetch" href="/assets/js/189.a8701dec.js"><link rel="prefetch" href="/assets/js/19.ca7db8ea.js"><link rel="prefetch" href="/assets/js/190.ae3d3bde.js"><link rel="prefetch" href="/assets/js/191.ad7cd44e.js"><link rel="prefetch" href="/assets/js/192.bc443842.js"><link rel="prefetch" href="/assets/js/193.e4755764.js"><link rel="prefetch" href="/assets/js/194.814112ce.js"><link rel="prefetch" href="/assets/js/195.1c0aaa80.js"><link rel="prefetch" href="/assets/js/196.a6bd7add.js"><link rel="prefetch" href="/assets/js/20.4e91cd31.js"><link rel="prefetch" href="/assets/js/21.f095e6e1.js"><link rel="prefetch" href="/assets/js/22.72f4b8ab.js"><link rel="prefetch" href="/assets/js/23.e94eb9d2.js"><link rel="prefetch" href="/assets/js/24.0eae7d6f.js"><link rel="prefetch" href="/assets/js/25.36157609.js"><link rel="prefetch" href="/assets/js/26.dc5b6cba.js"><link rel="prefetch" href="/assets/js/27.c19b7b63.js"><link rel="prefetch" href="/assets/js/28.3aceae59.js"><link rel="prefetch" href="/assets/js/29.536091b3.js"><link rel="prefetch" href="/assets/js/3.d11119c4.js"><link rel="prefetch" href="/assets/js/30.821a4a30.js"><link rel="prefetch" href="/assets/js/31.5238784c.js"><link rel="prefetch" href="/assets/js/32.10bc7179.js"><link rel="prefetch" href="/assets/js/33.c1ed69c9.js"><link rel="prefetch" href="/assets/js/34.8d384231.js"><link rel="prefetch" href="/assets/js/35.d8890e52.js"><link rel="prefetch" href="/assets/js/36.eca37ad5.js"><link rel="prefetch" href="/assets/js/37.802549e3.js"><link rel="prefetch" href="/assets/js/38.53841770.js"><link rel="prefetch" href="/assets/js/39.7ae44409.js"><link rel="prefetch" href="/assets/js/4.493b9bca.js"><link rel="prefetch" href="/assets/js/40.ce56364a.js"><link rel="prefetch" href="/assets/js/41.85f0114b.js"><link rel="prefetch" href="/assets/js/42.714da6e2.js"><link rel="prefetch" href="/assets/js/43.fee4437c.js"><link rel="prefetch" href="/assets/js/44.b039b68b.js"><link rel="prefetch" href="/assets/js/45.96a55605.js"><link rel="prefetch" href="/assets/js/46.956ffb03.js"><link rel="prefetch" href="/assets/js/47.147d9218.js"><link rel="prefetch" href="/assets/js/48.ff787b40.js"><link rel="prefetch" href="/assets/js/49.871eee87.js"><link rel="prefetch" href="/assets/js/5.e0ba07d7.js"><link rel="prefetch" href="/assets/js/50.99b7c29e.js"><link rel="prefetch" href="/assets/js/51.8ecbf4ba.js"><link rel="prefetch" href="/assets/js/52.53d91d7e.js"><link rel="prefetch" href="/assets/js/53.af8a0d2a.js"><link rel="prefetch" href="/assets/js/54.a2f848b5.js"><link rel="prefetch" href="/assets/js/55.267e9947.js"><link rel="prefetch" href="/assets/js/56.0b201c40.js"><link rel="prefetch" href="/assets/js/57.cbdfd6f7.js"><link rel="prefetch" href="/assets/js/58.636c0c3f.js"><link rel="prefetch" href="/assets/js/59.fc9216c4.js"><link rel="prefetch" href="/assets/js/6.b98373f2.js"><link rel="prefetch" href="/assets/js/60.34f16fc4.js"><link rel="prefetch" href="/assets/js/61.4d130bd8.js"><link rel="prefetch" href="/assets/js/62.927caa10.js"><link rel="prefetch" href="/assets/js/63.a451fee0.js"><link rel="prefetch" href="/assets/js/64.32a5d47b.js"><link rel="prefetch" href="/assets/js/65.bc099429.js"><link rel="prefetch" href="/assets/js/66.3953050d.js"><link rel="prefetch" href="/assets/js/67.e934823b.js"><link rel="prefetch" href="/assets/js/68.4bcb52b0.js"><link rel="prefetch" href="/assets/js/69.bede18c8.js"><link rel="prefetch" href="/assets/js/7.8de8df2d.js"><link rel="prefetch" href="/assets/js/70.fce1daac.js"><link rel="prefetch" href="/assets/js/71.ea0a8c5d.js"><link rel="prefetch" href="/assets/js/72.15382c9e.js"><link rel="prefetch" href="/assets/js/73.848364d3.js"><link rel="prefetch" href="/assets/js/74.5fd08a50.js"><link rel="prefetch" href="/assets/js/75.c937c70d.js"><link rel="prefetch" href="/assets/js/76.a0dacd5a.js"><link rel="prefetch" href="/assets/js/77.4019cc23.js"><link rel="prefetch" href="/assets/js/78.9676a9e1.js"><link rel="prefetch" href="/assets/js/79.e46e10d5.js"><link rel="prefetch" href="/assets/js/8.2098eb96.js"><link rel="prefetch" href="/assets/js/80.987e83cb.js"><link rel="prefetch" href="/assets/js/81.eb98ff36.js"><link rel="prefetch" href="/assets/js/82.623561a7.js"><link rel="prefetch" href="/assets/js/83.e256d909.js"><link rel="prefetch" href="/assets/js/84.7d06a550.js"><link rel="prefetch" href="/assets/js/85.b8d9879e.js"><link rel="prefetch" href="/assets/js/86.31c4581b.js"><link rel="prefetch" href="/assets/js/87.e06ee05e.js"><link rel="prefetch" href="/assets/js/88.81ef718d.js"><link rel="prefetch" href="/assets/js/89.ba237d2f.js"><link rel="prefetch" href="/assets/js/9.36092fd0.js"><link rel="prefetch" href="/assets/js/90.ad2c9d92.js"><link rel="prefetch" href="/assets/js/91.a661f52d.js"><link rel="prefetch" href="/assets/js/92.1c28035b.js"><link rel="prefetch" href="/assets/js/93.c8b8e3d6.js"><link rel="prefetch" href="/assets/js/94.b6bc4a44.js"><link rel="prefetch" href="/assets/js/95.92cea882.js"><link rel="prefetch" href="/assets/js/96.5373491b.js"><link rel="prefetch" href="/assets/js/97.bb39efc8.js"><link rel="prefetch" href="/assets/js/98.af7a030f.js"><link rel="prefetch" href="/assets/js/99.07dc87d8.js">
    <link rel="stylesheet" href="/assets/css/0.styles.d9c8cf8c.css">
  </head>
  <body class="theme-mode-light">
    <div id="app" data-server-rendered="true"><div class="theme-container sidebar-open have-rightmenu"><header class="navbar blur"><div title="目录" class="sidebar-button"><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" role="img" viewBox="0 0 448 512" class="icon"><path fill="currentColor" d="M436 124H12c-6.627 0-12-5.373-12-12V80c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12z"></path></svg></div> <a href="/" class="home-link router-link-active"><img src="https://lingxin-tanhua.oss-cn-shanghai.aliyuncs.com/QQ%E6%88%AA%E5%9B%BE20220503092755.png" alt="凌歆的博客" class="logo"> <span class="site-name can-hide">凌歆的博客</span></a> <div class="links"><div class="search-box"><input aria-label="Search" autocomplete="off" spellcheck="false" value=""> <!----></div> <nav class="nav-links can-hide"><div class="nav-item"><a href="/" class="nav-link">首页</a></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="前端" class="dropdown-title"><a href="/web/" class="link-title">前端</a> <span class="title" style="display:none;">前端</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><h4>学习笔记</h4> <ul class="dropdown-subitem-wrapper"><li class="dropdown-subitem"><a href="/note/html/" class="nav-link">HTML笔记</a></li><li class="dropdown-subitem"><a href="/note/js-low/" class="nav-link">JavaScript基础笔记</a></li><li class="dropdown-subitem"><a href="/note/js-high/" class="nav-link">JavaScript高阶笔记</a></li><li class="dropdown-subitem"><a href="/note/js-dom-bom/" class="nav-link">JavaScript DOM和BOM笔记</a></li><li class="dropdown-subitem"><a href="/note/jquery/" class="nav-link">jQuery笔记</a></li><li class="dropdown-subitem"><a href="/note/ajax/" class="nav-link">Ajax笔记</a></li><li class="dropdown-subitem"><a href="/note/nodejs/" class="nav-link">NodeJs笔记</a></li><li class="dropdown-subitem"><a href="/note/reg/" class="nav-link">正则表达式笔记</a></li><li class="dropdown-subitem"><a href="/note/vue/" class="nav-link">Vue笔记</a></li><li class="dropdown-subitem"><a href="/note/react/" class="nav-link">react笔记</a></li><li class="dropdown-subitem"><a href="/note/wx/" class="nav-link">微信小程序笔记</a></li><li class="dropdown-subitem"><a href="/note/uniapp/" class="nav-link">uniapp笔记</a></li><li class="dropdown-subitem"><a href="/note/echarts/" class="nav-link">echarts笔记</a></li><li class="dropdown-subitem"><a href="/note/git/" class="nav-link">Git笔记</a></li></ul></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="后端" class="dropdown-title"><a href="/back/" class="link-title">后端</a> <span class="title" style="display:none;">后端</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/java/" class="nav-link">JAVA</a></li><li class="dropdown-item"><!----> <a href="/note/javaweb/" class="nav-link">JavaWeb</a></li><li class="dropdown-item"><!----> <a href="/note/mysql/" class="nav-link">MySql</a></li><li class="dropdown-item"><!----> <a href="/note/ssm/" class="nav-link">ssm</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="算法" class="dropdown-title"><a href="/algor/" class="link-title">算法</a> <span class="title" style="display:none;">算法</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/sf/" class="nav-link">算法训练营</a></li><li class="dropdown-item"><!----> <a href="/note/js-sf/" class="nav-link">js数据结构与算法</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="面试" class="dropdown-title"><a href="/mianshi/" class="link-title">面试</a> <span class="title" style="display:none;">面试</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/lqb/" class="nav-link">蓝桥杯备战</a></li><li class="dropdown-item"><!----> <a href="/note/ms/" class="nav-link">前端面试</a></li><li class="dropdown-item"><!----> <a href="/note/hmms/" class="nav-link">黑马面试</a></li><li class="dropdown-item"><!----> <a href="/note/xzms/" class="nav-link">校招零距离面试</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="解决方案" class="dropdown-title"><a href="/resolve/" class="link-title">解决方案</a> <span class="title" style="display:none;">解决方案</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/qd-resolve/" class="nav-link">前端解决方案</a></li><li class="dropdown-item"><!----> <a href="/note/hd-resolve/" class="nav-link">后端解决方案</a></li></ul></div></div><div class="nav-item"><a href="/pages/beb6c0bd8a66cea6/" class="nav-link">收藏</a></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="索引" class="dropdown-title"><a href="/archives/" class="link-title">索引</a> <span class="title" style="display:none;">索引</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/categories/" class="nav-link">分类</a></li><li class="dropdown-item"><!----> <a href="/tags/" class="nav-link">标签</a></li><li class="dropdown-item"><!----> <a href="/archives/" class="nav-link">归档</a></li></ul></div></div> <a href="https://github.com/linxin1123/vuepress-blog" target="_blank" rel="noopener noreferrer" class="repo-link">
    GitHub
    <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></nav></div></header> <div class="sidebar-mask"></div> <div class="sidebar-hover-trigger"></div> <aside class="sidebar" style="display:none;"><div class="blogger"><img src="https://lingxin-tanhua.oss-cn-shanghai.aliyuncs.com/QQ%E6%88%AA%E5%9B%BE20220503092755.png"> <div class="blogger-info"><h3>lingxin</h3> <span>凌歆</span></div></div> <nav class="nav-links"><div class="nav-item"><a href="/" class="nav-link">首页</a></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="前端" class="dropdown-title"><a href="/web/" class="link-title">前端</a> <span class="title" style="display:none;">前端</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><h4>学习笔记</h4> <ul class="dropdown-subitem-wrapper"><li class="dropdown-subitem"><a href="/note/html/" class="nav-link">HTML笔记</a></li><li class="dropdown-subitem"><a href="/note/js-low/" class="nav-link">JavaScript基础笔记</a></li><li class="dropdown-subitem"><a href="/note/js-high/" class="nav-link">JavaScript高阶笔记</a></li><li class="dropdown-subitem"><a href="/note/js-dom-bom/" class="nav-link">JavaScript DOM和BOM笔记</a></li><li class="dropdown-subitem"><a href="/note/jquery/" class="nav-link">jQuery笔记</a></li><li class="dropdown-subitem"><a href="/note/ajax/" class="nav-link">Ajax笔记</a></li><li class="dropdown-subitem"><a href="/note/nodejs/" class="nav-link">NodeJs笔记</a></li><li class="dropdown-subitem"><a href="/note/reg/" class="nav-link">正则表达式笔记</a></li><li class="dropdown-subitem"><a href="/note/vue/" class="nav-link">Vue笔记</a></li><li class="dropdown-subitem"><a href="/note/react/" class="nav-link">react笔记</a></li><li class="dropdown-subitem"><a href="/note/wx/" class="nav-link">微信小程序笔记</a></li><li class="dropdown-subitem"><a href="/note/uniapp/" class="nav-link">uniapp笔记</a></li><li class="dropdown-subitem"><a href="/note/echarts/" class="nav-link">echarts笔记</a></li><li class="dropdown-subitem"><a href="/note/git/" class="nav-link">Git笔记</a></li></ul></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="后端" class="dropdown-title"><a href="/back/" class="link-title">后端</a> <span class="title" style="display:none;">后端</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/java/" class="nav-link">JAVA</a></li><li class="dropdown-item"><!----> <a href="/note/javaweb/" class="nav-link">JavaWeb</a></li><li class="dropdown-item"><!----> <a href="/note/mysql/" class="nav-link">MySql</a></li><li class="dropdown-item"><!----> <a href="/note/ssm/" class="nav-link">ssm</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="算法" class="dropdown-title"><a href="/algor/" class="link-title">算法</a> <span class="title" style="display:none;">算法</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/sf/" class="nav-link">算法训练营</a></li><li class="dropdown-item"><!----> <a href="/note/js-sf/" class="nav-link">js数据结构与算法</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="面试" class="dropdown-title"><a href="/mianshi/" class="link-title">面试</a> <span class="title" style="display:none;">面试</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/lqb/" class="nav-link">蓝桥杯备战</a></li><li class="dropdown-item"><!----> <a href="/note/ms/" class="nav-link">前端面试</a></li><li class="dropdown-item"><!----> <a href="/note/hmms/" class="nav-link">黑马面试</a></li><li class="dropdown-item"><!----> <a href="/note/xzms/" class="nav-link">校招零距离面试</a></li></ul></div></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="解决方案" class="dropdown-title"><a href="/resolve/" class="link-title">解决方案</a> <span class="title" style="display:none;">解决方案</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/note/qd-resolve/" class="nav-link">前端解决方案</a></li><li class="dropdown-item"><!----> <a href="/note/hd-resolve/" class="nav-link">后端解决方案</a></li></ul></div></div><div class="nav-item"><a href="/pages/beb6c0bd8a66cea6/" class="nav-link">收藏</a></div><div class="nav-item"><div class="dropdown-wrapper"><button type="button" aria-label="索引" class="dropdown-title"><a href="/archives/" class="link-title">索引</a> <span class="title" style="display:none;">索引</span> <span class="arrow right"></span></button> <ul class="nav-dropdown" style="display:none;"><li class="dropdown-item"><!----> <a href="/categories/" class="nav-link">分类</a></li><li class="dropdown-item"><!----> <a href="/tags/" class="nav-link">标签</a></li><li class="dropdown-item"><!----> <a href="/archives/" class="nav-link">归档</a></li></ul></div></div> <a href="https://github.com/linxin1123/vuepress-blog" target="_blank" rel="noopener noreferrer" class="repo-link">
    GitHub
    <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></nav>  <ul class="sidebar-links"><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>学习笔记</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>算法训练营</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading open"><span>js数据结构与算法</span> <span class="arrow down"></span></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/pages/832d5e/" class="sidebar-link">排序</a></li><li><a href="/pages/0495c3/" aria-current="page" class="active sidebar-link">图-cnblog</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level2"><a href="/pages/0495c3/#图" class="sidebar-link">图</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header level3"><a href="/pages/0495c3/#图的表示法" class="sidebar-link">图的表示法</a></li><li class="sidebar-sub-header level3"><a href="/pages/0495c3/#图的遍历" class="sidebar-link">图的遍历</a></li><li class="sidebar-sub-header level3"><a href="/pages/0495c3/#leetcode-题目" class="sidebar-link">LeetCode 题目</a></li><li class="sidebar-sub-header level4"><a href="/pages/0495c3/#_65-有效数字" class="sidebar-link">65. 有效数字</a></li><li class="sidebar-sub-header level5"><a href="/pages/0495c3/#解题思路" class="sidebar-link">解题思路</a></li><li class="sidebar-sub-header level4"><a href="/pages/0495c3/#_417-太平洋大西洋水流问题" class="sidebar-link">417. 太平洋大西洋水流问题</a></li><li class="sidebar-sub-header level5"><a href="/pages/0495c3/#解题思路-2" class="sidebar-link">解题思路</a></li></ul></li></ul></li><li><a href="/pages/bdcc1b/" class="sidebar-link">堆-cnblog</a></li><li><a href="/pages/5379fb/" class="sidebar-link">贪心算法-cnblog</a></li><li><a href="/pages/ce13b0/" class="sidebar-link">动态规划</a></li><li><a href="/pages/6d8cb6/" class="sidebar-link">分治</a></li><li><a href="/pages/eec625/" class="sidebar-link">回溯</a></li></ul></section></li></ul> </aside> <div><main class="page"><div class="theme-vdoing-wrapper "><div class="articleInfo-wrap" data-v-06225672><div class="articleInfo" data-v-06225672><ul class="breadcrumbs" data-v-06225672><li data-v-06225672><a href="/" title="首页" class="iconfont icon-home router-link-active" data-v-06225672></a></li> <li data-v-06225672><a href="/algor/#算法" data-v-06225672>算法</a></li><li data-v-06225672><a href="/algor/#js数据结构与算法" data-v-06225672>js数据结构与算法</a></li></ul> <div class="info" data-v-06225672><div title="作者" class="author iconfont icon-touxiang" data-v-06225672><a href="https://github.com/linxin1123" target="_blank" title="作者" class="beLink" data-v-06225672>lingxin</a></div> <div title="创建时间" class="date iconfont icon-riqi" data-v-06225672><a href="javascript:;" data-v-06225672>2023-02-17</a></div> <!----></div></div></div> <!----> <div class="content-wrapper"><div class="right-menu-wrapper"><div class="right-menu-margin"><div class="right-menu-title">目录</div> <div class="right-menu-content"></div></div></div> <h1><img src="">图-cnblog<!----></h1>  <div class="theme-vdoing-content content__default"><h2 id="图"><a href="#图" class="header-anchor">#</a> 图</h2> <ul><li>一个二元关系</li></ul> <h3 id="图的表示法"><a href="#图的表示法" class="header-anchor">#</a> 图的表示法</h3> <ul><li>邻接矩阵
<ul><li><img src="https://img2023.cnblogs.com/blog/3089561/202302/3089561-20230205100506275-919527854.png" alt=""></li></ul></li> <li>邻接表
<ul><li><img src="https://img2023.cnblogs.com/blog/3089561/202302/3089561-20230205100505840-811289047.png" alt=""></li></ul></li></ul> <h3 id="图的遍历"><a href="#图的遍历" class="header-anchor">#</a> 图的遍历</h3> <ul><li>深度优先搜索
<ol><li>访问根节点（开始节点）</li> <li>循环访问没有访问过的邻接节点（递归，新节点跳回第一步）</li></ol></li> <li>广度优先搜索
<ol><li>维护一个队列</li> <li>节点入队（第一次开始节点）</li> <li>节点出队并访问，把当前节点没有访问过的邻接节点入队（循环第三步，直到队列为空）</li></ol></li></ul> <h3 id="leetcode-题目"><a href="#leetcode-题目" class="header-anchor">#</a> LeetCode 题目</h3> <h4 id="_65-有效数字"><a href="#_65-有效数字" class="header-anchor">#</a> <a href="https://leetcode.cn/problems/valid-number/" target="_blank" rel="noopener noreferrer">65. 有效数字<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></h4> <p><strong>有效数字</strong>（按顺序）可以分成以下几个部分：</p> <ol><li>一个 <strong>小数</strong> 或者 <strong>整数</strong></li> <li>（可选）一个 <code>'e'</code> 或 <code>'E'</code> ，后面跟着一个 <strong>整数</strong></li></ol> <p><strong>小数</strong>（按顺序）可以分成以下几个部分：</p> <ol><li>（可选）一个符号字符（<code>'+'</code> 或 <code>'-'</code>）</li> <li>下述格式之一：
<ol><li>至少一位数字，后面跟着一个点 <code>'.'</code></li> <li>至少一位数字，后面跟着一个点 <code>'.'</code> ，后面再跟着至少一位数字</li> <li>一个点 <code>'.'</code> ，后面跟着至少一位数字</li></ol></li></ol> <p><strong>整数</strong>（按顺序）可以分成以下几个部分：</p> <ol><li>（可选）一个符号字符（<code>'+'</code> 或 <code>'-'</code>）</li> <li>至少一位数字</li></ol> <p>部分有效数字列举如下：<code>[&quot;2&quot;, &quot;0089&quot;, &quot;-0.1&quot;, &quot;+3.14&quot;, &quot;4.&quot;, &quot;-.9&quot;, &quot;2e10&quot;, &quot;-90E3&quot;, &quot;3e+7&quot;, &quot;+6e-1&quot;, &quot;53.5e93&quot;, &quot;-123.456e789&quot;]</code></p> <p>部分无效数字列举如下：<code>[&quot;abc&quot;, &quot;1a&quot;, &quot;1e&quot;, &quot;e3&quot;, &quot;99e2.5&quot;, &quot;--6&quot;, &quot;-+3&quot;, &quot;95a54e53&quot;]</code></p> <p>给你一个字符串 <code>s</code> ，如果 <code>s</code> 是一个 <strong>有效数字</strong> ，请返回 <code>true</code> 。</p> <p><strong>示例 1：</strong></p> <div class="language- line-numbers-mode"><pre class="language-text"><code>输入：s = &quot;0&quot;
输出：true
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p><strong>示例 2：</strong></p> <div class="language- line-numbers-mode"><pre class="language-text"><code>输入：s = &quot;e&quot;
输出：false
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p><strong>示例 3：</strong></p> <div class="language- line-numbers-mode"><pre class="language-text"><code>输入：s = &quot;.&quot;
输出：false
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p><strong>提示：</strong></p> <ul><li><code>1 &lt;= s.length &lt;= 20</code></li> <li><code>s</code> 仅含英文字母（大写和小写），数字（<code>0-9</code>），加号 <code>'+'</code> ，减号 <code>'-'</code> ，或者点 <code>'.'</code> 。</li></ul> <h5 id="解题思路"><a href="#解题思路" class="header-anchor">#</a> 解题思路</h5> <ul><li><p>使用刚刚学习的图</p></li> <li><p>有效状态自动机</p> <div class="language-js line-numbers-mode"><pre class="language-js"><code>	<span class="token comment">// blank 表示空格</span>
    <span class="token comment">// sign 表示正负号</span>
    <span class="token comment">// digit 表示数字</span>
    <span class="token comment">// dot 就是小数点</span>
    <span class="token comment">// e 就是 e</span>

    <span class="token comment">// 初态0</span>

    <span class="token keyword">const</span> graph<span class="token operator">=</span><span class="token punctuation">{</span>
        <span class="token comment">// 每次可以的走法，即加上一个新的字符会怎样</span>
            
        <span class="token comment">// 空格        </span>
        <span class="token number">0</span><span class="token operator">:</span><span class="token punctuation">{</span><span class="token string-property property">'blank'</span><span class="token operator">:</span><span class="token number">0</span><span class="token punctuation">,</span><span class="token string-property property">'digit'</span><span class="token operator">:</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token string-property property">'dot'</span><span class="token operator">:</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token string-property property">'sign'</span><span class="token operator">:</span><span class="token number">3</span><span class="token punctuation">}</span><span class="token punctuation">,</span>
        <span class="token comment">// [0-9] 满足</span>
        <span class="token number">1</span><span class="token operator">:</span><span class="token punctuation">{</span><span class="token string-property property">'digit'</span><span class="token operator">:</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token string-property property">'dot'</span><span class="token operator">:</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token string-property property">'e'</span><span class="token operator">:</span><span class="token number">5</span><span class="token punctuation">,</span><span class="token string-property property">'E'</span><span class="token operator">:</span><span class="token number">5</span><span class="token punctuation">}</span><span class="token punctuation">,</span>
        <span class="token comment">// .</span>
        <span class="token number">2</span><span class="token operator">:</span><span class="token punctuation">{</span><span class="token string-property property">'digit'</span><span class="token operator">:</span><span class="token number">4</span><span class="token punctuation">}</span><span class="token punctuation">,</span>
        <span class="token comment">// [+-]</span>
        <span class="token number">3</span><span class="token operator">:</span><span class="token punctuation">{</span><span class="token string-property property">'digit'</span><span class="token operator">:</span><span class="token number">1</span><span class="token punctuation">,</span><span class="token string-property property">'dot'</span><span class="token operator">:</span><span class="token number">2</span><span class="token punctuation">,</span><span class="token punctuation">}</span><span class="token punctuation">,</span>
        <span class="token comment">// [0-9]. .[0-9] 满足</span>
        <span class="token number">4</span><span class="token operator">:</span><span class="token punctuation">{</span><span class="token string-property property">'digit'</span><span class="token operator">:</span><span class="token number">4</span><span class="token punctuation">,</span><span class="token string-property property">'e'</span><span class="token operator">:</span><span class="token number">5</span><span class="token punctuation">,</span><span class="token string-property property">'E'</span><span class="token operator">:</span><span class="token number">5</span><span class="token punctuation">}</span><span class="token punctuation">,</span>
        <span class="token comment">// .[0-9][e/E] [0-9].[e/E]</span>
        <span class="token number">5</span><span class="token operator">:</span><span class="token punctuation">{</span><span class="token string-property property">'sign'</span><span class="token operator">:</span><span class="token number">6</span><span class="token punctuation">,</span><span class="token string-property property">'digit'</span><span class="token operator">:</span><span class="token number">7</span><span class="token punctuation">}</span><span class="token punctuation">,</span>
        
        <span class="token comment">// .[0-9][e/E][+-] [0-9].[e/E][+-]</span>
        <span class="token number">6</span><span class="token operator">:</span><span class="token punctuation">{</span><span class="token string-property property">'digit'</span><span class="token operator">:</span><span class="token number">7</span><span class="token punctuation">}</span><span class="token punctuation">,</span>

        <span class="token comment">// 满足</span>
        <span class="token number">7</span><span class="token operator">:</span><span class="token punctuation">{</span><span class="token string-property property">'digit'</span><span class="token operator">:</span><span class="token number">7</span><span class="token punctuation">}</span>
        
<span class="token punctuation">}</span>
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br></div></div></li> <li><p>符合题意的状态</p> <div class="language-shell line-numbers-mode"><pre class="language-shell"><code><span class="token number">1,4</span>,7
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br></div></div></li> <li><p>完整代码</p></li></ul> <div class="language-js line-numbers-mode"><pre class="language-js"><code><span class="token comment">/**
 * @param {string} s
 * @return {boolean}
 */</span>
<span class="token keyword">var</span> <span class="token function-variable function">isNumber</span> <span class="token operator">=</span> <span class="token keyword">function</span> <span class="token punctuation">(</span><span class="token parameter">s</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
  <span class="token comment">// blank 表示空格</span>
  <span class="token comment">// sign 表示正负号</span>
  <span class="token comment">// digit 表示数字</span>
  <span class="token comment">// dot 就是小数点</span>
  <span class="token comment">// e 就是 e</span>

  <span class="token comment">// 初态0</span>

  <span class="token keyword">const</span> graph <span class="token operator">=</span> <span class="token punctuation">{</span>
    <span class="token comment">// 每次可以的走法，即加上一个新的字符会怎样</span>

    <span class="token comment">// 空格</span>
    <span class="token number">0</span><span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token literal-property property">blank</span><span class="token operator">:</span> <span class="token number">0</span><span class="token punctuation">,</span> <span class="token literal-property property">digit</span><span class="token operator">:</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token literal-property property">dot</span><span class="token operator">:</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token literal-property property">sign</span><span class="token operator">:</span> <span class="token number">3</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>
    <span class="token comment">// [0-9] 满足</span>
    <span class="token number">1</span><span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token literal-property property">digit</span><span class="token operator">:</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token literal-property property">dot</span><span class="token operator">:</span> <span class="token number">4</span><span class="token punctuation">,</span> <span class="token literal-property property">e</span><span class="token operator">:</span> <span class="token number">5</span><span class="token punctuation">,</span> <span class="token constant">E</span><span class="token operator">:</span> <span class="token number">5</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>
    <span class="token comment">// .</span>
    <span class="token number">2</span><span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token literal-property property">digit</span><span class="token operator">:</span> <span class="token number">4</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>
    <span class="token comment">// [+-]</span>
    <span class="token number">3</span><span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token literal-property property">digit</span><span class="token operator">:</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token literal-property property">dot</span><span class="token operator">:</span> <span class="token number">2</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>
    <span class="token comment">// [0-9]. .[0-9] 满足</span>
    <span class="token number">4</span><span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token literal-property property">digit</span><span class="token operator">:</span> <span class="token number">4</span><span class="token punctuation">,</span> <span class="token literal-property property">e</span><span class="token operator">:</span> <span class="token number">5</span><span class="token punctuation">,</span> <span class="token constant">E</span><span class="token operator">:</span> <span class="token number">5</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>
    <span class="token comment">// .[0-9][e/E] [0-9].[e/E]</span>
    <span class="token number">5</span><span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token literal-property property">sign</span><span class="token operator">:</span> <span class="token number">6</span><span class="token punctuation">,</span> <span class="token literal-property property">digit</span><span class="token operator">:</span> <span class="token number">7</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>

    <span class="token comment">// .[0-9][e/E][+-] [0-9].[e/E][+-]</span>
    <span class="token number">6</span><span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token literal-property property">digit</span><span class="token operator">:</span> <span class="token number">7</span> <span class="token punctuation">}</span><span class="token punctuation">,</span>

    <span class="token comment">// 满足</span>
    <span class="token number">7</span><span class="token operator">:</span> <span class="token punctuation">{</span> <span class="token literal-property property">digit</span><span class="token operator">:</span> <span class="token number">7</span> <span class="token punctuation">}</span>
  <span class="token punctuation">}</span>

  <span class="token comment">// 遍历字符串</span>

  <span class="token keyword">let</span> state <span class="token operator">=</span> <span class="token number">0</span>

  <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">let</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator">&lt;</span> s<span class="token punctuation">.</span>length<span class="token punctuation">;</span> i<span class="token operator">++</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token comment">// console.log(s[i])</span>

    <span class="token comment">// console.log(parseInt(s[i])-48)</span>

    <span class="token comment">// if(s[i]-48&gt;=0 &amp;&amp; s[i]-48&lt;=9){</span>
    <span class="token comment">//     console.log(s[i])</span>
    <span class="token comment">// }</span>

    <span class="token comment">// console.log(s[i].charCodeAt())</span>

    <span class="token keyword">let</span> code <span class="token operator">=</span> s<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">.</span><span class="token function">charCodeAt</span><span class="token punctuation">(</span><span class="token punctuation">)</span>

    <span class="token keyword">if</span> <span class="token punctuation">(</span>code <span class="token operator">-</span> <span class="token number">48</span> <span class="token operator">&gt;=</span> <span class="token number">0</span> <span class="token operator">&amp;&amp;</span> code <span class="token operator">-</span> <span class="token number">48</span> <span class="token operator">&lt;=</span> <span class="token number">9</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      state <span class="token operator">=</span> graph<span class="token punctuation">[</span>state<span class="token punctuation">]</span><span class="token punctuation">[</span><span class="token string">'digit'</span><span class="token punctuation">]</span>
    <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>s<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">===</span> <span class="token string">'e'</span> <span class="token operator">||</span> s<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">===</span> <span class="token string">'E'</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      state <span class="token operator">=</span> graph<span class="token punctuation">[</span>state<span class="token punctuation">]</span><span class="token punctuation">[</span><span class="token string">'e'</span><span class="token punctuation">]</span>
    <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>s<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">===</span> <span class="token string">'.'</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      state <span class="token operator">=</span> graph<span class="token punctuation">[</span>state<span class="token punctuation">]</span><span class="token punctuation">[</span><span class="token string">'dot'</span><span class="token punctuation">]</span>
    <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token keyword">if</span> <span class="token punctuation">(</span>s<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">===</span> <span class="token string">'+'</span> <span class="token operator">||</span> s<span class="token punctuation">[</span>i<span class="token punctuation">]</span> <span class="token operator">===</span> <span class="token string">'-'</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
      state <span class="token operator">=</span> graph<span class="token punctuation">[</span>state<span class="token punctuation">]</span><span class="token punctuation">[</span><span class="token string">'sign'</span><span class="token punctuation">]</span>
    <span class="token punctuation">}</span> <span class="token keyword">else</span> <span class="token punctuation">{</span>
      <span class="token keyword">return</span> <span class="token boolean">false</span>
    <span class="token punctuation">}</span>

    console<span class="token punctuation">.</span><span class="token function">log</span><span class="token punctuation">(</span>state<span class="token punctuation">)</span>

    <span class="token keyword">if</span> <span class="token punctuation">(</span><span class="token operator">!</span>state<span class="token punctuation">)</span> <span class="token punctuation">{</span>
      <span class="token keyword">return</span> <span class="token boolean">false</span>
    <span class="token punctuation">}</span>
  <span class="token punctuation">}</span>

  <span class="token keyword">if</span> <span class="token punctuation">(</span>state <span class="token operator">===</span> <span class="token number">1</span> <span class="token operator">||</span> state <span class="token operator">===</span> <span class="token number">4</span> <span class="token operator">||</span> state <span class="token operator">===</span> <span class="token number">7</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
    <span class="token keyword">return</span> <span class="token boolean">true</span>
  <span class="token punctuation">}</span>

  <span class="token keyword">return</span> <span class="token boolean">false</span>
<span class="token punctuation">}</span>

</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br><span class="line-number">4</span><br><span class="line-number">5</span><br><span class="line-number">6</span><br><span class="line-number">7</span><br><span class="line-number">8</span><br><span class="line-number">9</span><br><span class="line-number">10</span><br><span class="line-number">11</span><br><span class="line-number">12</span><br><span class="line-number">13</span><br><span class="line-number">14</span><br><span class="line-number">15</span><br><span class="line-number">16</span><br><span class="line-number">17</span><br><span class="line-number">18</span><br><span class="line-number">19</span><br><span class="line-number">20</span><br><span class="line-number">21</span><br><span class="line-number">22</span><br><span class="line-number">23</span><br><span class="line-number">24</span><br><span class="line-number">25</span><br><span class="line-number">26</span><br><span class="line-number">27</span><br><span class="line-number">28</span><br><span class="line-number">29</span><br><span class="line-number">30</span><br><span class="line-number">31</span><br><span class="line-number">32</span><br><span class="line-number">33</span><br><span class="line-number">34</span><br><span class="line-number">35</span><br><span class="line-number">36</span><br><span class="line-number">37</span><br><span class="line-number">38</span><br><span class="line-number">39</span><br><span class="line-number">40</span><br><span class="line-number">41</span><br><span class="line-number">42</span><br><span class="line-number">43</span><br><span class="line-number">44</span><br><span class="line-number">45</span><br><span class="line-number">46</span><br><span class="line-number">47</span><br><span class="line-number">48</span><br><span class="line-number">49</span><br><span class="line-number">50</span><br><span class="line-number">51</span><br><span class="line-number">52</span><br><span class="line-number">53</span><br><span class="line-number">54</span><br><span class="line-number">55</span><br><span class="line-number">56</span><br><span class="line-number">57</span><br><span class="line-number">58</span><br><span class="line-number">59</span><br><span class="line-number">60</span><br><span class="line-number">61</span><br><span class="line-number">62</span><br><span class="line-number">63</span><br><span class="line-number">64</span><br><span class="line-number">65</span><br><span class="line-number">66</span><br><span class="line-number">67</span><br><span class="line-number">68</span><br><span class="line-number">69</span><br><span class="line-number">70</span><br><span class="line-number">71</span><br><span class="line-number">72</span><br><span class="line-number">73</span><br><span class="line-number">74</span><br><span class="line-number">75</span><br><span class="line-number">76</span><br><span class="line-number">77</span><br><span class="line-number">78</span><br><span class="line-number">79</span><br></div></div><h4 id="_417-太平洋大西洋水流问题"><a href="#_417-太平洋大西洋水流问题" class="header-anchor">#</a> <a href="https://leetcode.cn/problems/pacific-atlantic-water-flow/" target="_blank" rel="noopener noreferrer">417. 太平洋大西洋水流问题<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></h4> <p>难度中等536收藏分享切换为英文接收动态反馈</p> <p>有一个 <code>m × n</code> 的矩形岛屿，与 <strong>太平洋</strong> 和 <strong>大西洋</strong> 相邻。 <strong>“太平洋”</strong> 处于大陆的左边界和上边界，而 <strong>“大西洋”</strong> 处于大陆的右边界和下边界。</p> <p>这个岛被分割成一个由若干方形单元格组成的网格。给定一个 <code>m x n</code> 的整数矩阵 <code>heights</code> ， <code>heights[r][c]</code> 表示坐标 <code>(r, c)</code> 上单元格 <strong>高于海平面的高度</strong> 。</p> <p>岛上雨水较多，如果相邻单元格的高度 <strong>小于或等于</strong> 当前单元格的高度，雨水可以直接向北、南、东、西流向相邻单元格。水可以从海洋附近的任何单元格流入海洋。</p> <p>返回网格坐标 <code>result</code> 的 <strong>2D 列表</strong> ，其中 <code>result[i] = [ri, ci]</code> 表示雨水从单元格 <code>(ri, ci)</code> 流动 <strong>既可流向太平洋也可流向大西洋</strong> 。</p> <p><strong>示例 1：</strong></p> <p><img src="https://assets.leetcode.com/uploads/2021/06/08/waterflow-grid.jpg" alt="img"></p> <div class="language- line-numbers-mode"><pre class="language-text"><code>输入: heights = [[1,2,2,3,5],[3,2,3,4,4],[2,4,5,3,1],[6,7,1,4,5],[5,1,1,2,4]]
输出: [[0,4],[1,3],[1,4],[2,2],[3,0],[3,1],[4,0]]
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p><strong>示例 2：</strong></p> <div class="language- line-numbers-mode"><pre class="language-text"><code>输入: heights = [[2,1],[1,2]]
输出: [[0,0],[0,1],[1,0],[1,1]]
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br></div></div><p><strong>提示：</strong></p> <ul><li><code>m == heights.length</code></li> <li><code>n == heights[r].length</code></li> <li><code>1 &lt;= m, n &lt;= 200</code></li> <li><code>0 &lt;= heights[r][c] &lt;= 105</code></li></ul> <h5 id="解题思路-2"><a href="#解题思路-2" class="header-anchor">#</a> 解题思路</h5> <div class="language- line-numbers-mode"><pre class="language-text"><code>1. 考虑使用深度优先搜索
2. 遍历矩阵四周可以逆流而上的所有格子
3. 同时向大西洋和太平洋逆流而上的所有格子
</code></pre> <div class="line-numbers-wrapper"><span class="line-number">1</span><br><span class="line-number">2</span><br><span class="line-number">3</span><br></div></div></div></div>  <div class="page-edit"><div class="edit-link"><a href="https://github.com/linxin1123/vuepress-blog/edit/master/docs/07.算法/42.js数据结构与算法/02.图-cnblog.md" target="_blank" rel="noopener noreferrer">编辑</a> <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></div> <!----> <div class="last-updated"><span class="prefix">上次更新:</span> <span class="time">2023/02/17, 11:29:32</span></div></div> <div class="page-nav-wapper"><div class="page-nav-centre-wrap"><a href="/pages/832d5e/" class="page-nav-centre page-nav-centre-prev"><div class="tooltip">排序</div></a> <a href="/pages/bdcc1b/" class="page-nav-centre page-nav-centre-next"><div class="tooltip">堆-cnblog</div></a></div> <div class="page-nav"><p class="inner"><span class="prev">
        ←
        <a href="/pages/832d5e/" class="prev">排序</a></span> <span class="next"><a href="/pages/bdcc1b/">堆-cnblog</a>→
      </span></p></div></div></div> <div class="article-list"><div class="article-title"><a href="/archives/" class="iconfont icon-bi">最近更新</a></div> <div class="article-wrapper"><dl><dd>01</dd> <dt><a href="/pages/0b785d/"><div>
            Vuex
            <!----></div></a> <span class="date">03-14</span></dt></dl><dl><dd>02</dd> <dt><a href="/pages/c59cc0/"><div>
            Vue响应式原理
            <!----></div></a> <span class="date">03-14</span></dt></dl><dl><dd>03</dd> <dt><a href="/pages/83cc7a/"><div>
            Vue虚拟DOM-cnblog
            <!----></div></a> <span class="date">03-14</span></dt></dl> <dl><dd></dd> <dt><a href="/archives/" class="more">更多文章&gt;</a></dt></dl></div></div></main></div> <div class="footer"><div class="icons"><a href="3010733382@qq.com" title="发邮件" target="_blank" class="iconfont icon-youjian"></a><a href="https://github.com/linxin1123" title="GitHub" target="_blank" class="iconfont icon-github"></a><a href="https://music.163.com/#/playlist?id=755597173" title="听音乐" target="_blank" class="iconfont icon-erji"></a></div> 
  Theme by
  <a href="https://github.com/xugaoyi/vuepress-theme-vdoing" target="_blank" title="本站主题">Vdoing</a> 
    | Copyright © 2022-2023
    <span>lingxin | <a href="https://github.com/linxin1123/vuepress-blog/blob/master/LICENSE" target="_blank">MIT License</a></span></div> <div class="buttons"><div title="返回顶部" class="button blur go-to-top iconfont icon-fanhuidingbu" style="display:none;"></div> <div title="去评论" class="button blur go-to-comment iconfont icon-pinglun" style="display:none;"></div> <div title="主题模式" class="button blur theme-mode-but iconfont icon-zhuti"><ul class="select-box" style="display:none;"><li class="iconfont icon-zidong">
          跟随系统
        </li><li class="iconfont icon-rijianmoshi">
          浅色模式
        </li><li class="iconfont icon-yejianmoshi">
          深色模式
        </li><li class="iconfont icon-yuedu">
          阅读模式
        </li></ul></div></div> <!----> <!----> <!----></div><div class="global-ui"><div></div></div></div>
    <script src="/assets/js/app.57550e13.js" defer></script><script src="/assets/js/2.f014c35f.js" defer></script><script src="/assets/js/114.e95a0131.js" defer></script>
  </body>
</html>
